Can Simulation Help to Find the Sources of Wheel Damages?: Investigation of Rolling Contact fatigue on the Wheels of a Three-Piece Bogie on the Swedish Iron ore Line via Multibody Simulation Considering Extreme Winter Condition

Bogojevic, Nebojsa

Abstract [en]

The Swedish iron ore company LKAB uses freight wagon with three-piece bogie to transport iron ore from the mines in Kiruna and Malmberget to Luleå and Narvik. A simulation model of the freight wagon has been built at KTH Rail Vehicles using the Multibody simulation code GENSYS. The purpose is to investigate possible sources of rolling contact fatigue (RCF) of the wheels given the high level of damage, particularly in the winter.The wooden sleeper track has recently been replaced by a stiffer track with concrete sleeper. After the change, the frequency of RCF increased. Therefore, both track models are implemented. A parameter study is performed on vertical track stiffness and viscous damping regarding the seasonal variations of the track conditions. Another parameter study is carried out on the influence of the wheel-rail friction coefficient because in winter time the climate is very dry along most parst of the Swedish iron-ore line. The impact of new and worn wheel profiles on RCF is investigated. The wear number is calculated and compared with the RCF probability.The shakedown map is used to study the influence of an increase in track forces on RCF. It is shown that RCF happens on the tread of the inner wheels while negotiating curves below approximately 450 m radius. And in cold dry climate conditions when the wheel-rail friction coefficient significantly increases and when the wheel material behaves more brittle, the risk of RCF is significantly increased while the wear rate is not high enough to wear out the initiated cracks. It is proven that using concrete sleepers and vertically stiffer track might increase the track forces but it cannot be the main reason for severe RCF during winter.